The present invention relates to a radiation concentrator, particularly for solar power station.
Such radiation concentrators for solar power station are known, essentially constituted by cylindrical reflectors with a parabolic base which concentrate the sun's rays on cylindrical tubes of circular section, disposed at the focus of the parabola and whose generatrices are parallel to those of the reflector, these tubes being passed through by a heat-transfer fluid. These concentrators present the advantage of allowing the production of parabolic reflectors with a large angular aperture which make it possible to dispose the heat-transfer tube near the center of gravity of the reflector, which promotes the mechanical resistance of the assembly of the concentrator and allows the concentrator to pivot about its center of gravity, minimizing the relative displacements of the heat-transfer tube, which simplifies the problems of tightness thereof.
Such concentrators present a relatively weak concentration and this is why it has been proposed to add to the parabolic reflector a so-called "CPC" type reflector, i.e. a reflector constituted by two cylindrical elements of which the elliptic base is symmetrical with respect to a central axis and of which one of the foci is constituted by the downstream end of the reflector element which is symmetrical thereto with respect to the central axis, and the other focus is constituted by the intersection of the straight line joining the downstream end of this element to the upstream end of the other element with the parabolic reflector opposite the tube conveying the heat transfer fluid.
However, in such concentrators, the increase in concentration furnished by the CPC is significantly manifested only for parabolic reflectors of small angular aperture, so that the manufacturers of collectors have preferred, for the reasons mentioned above, to employ cylindrical collectors associated with simple parabolic reflectors despite the relatively low concentration resulting therefrom.